Method of breaking formation of solid deposits



June 24, 1958 G. KRUKY 2,840,365

\METHOD OF BREAKING FORMATION OF SOLID DEPOSITS Filed June 7, 1955 2Sheets-Sheet 1 G. KRUK June 24, 1958 METHOD OF BREAKING FORMATION OFSOLID DEPOSITS 2 Sheets-Sheet 2 Filed June 7, 1955IIIII'IIIIII'III|||'I. lllllllzl ll|||'| "l llllllr'lilr Ufl w tes P nMETHOD OF BREAKING FORMATION on SOLID DEPOSITS Geri-it Krulr, Heiloo,Netherlands, assignor to N. V.

Springit, .Zandvoort, Netherlands, a Dutch limited-liability companyApplication June 7, 1955, Serial No. 513,847

Claims priority, application Netherlands June 11, 1954 7 Claims. (Cl.263-45) This invention relates to a method of breaking formations ofsolid deposits formed in a hot space such as an oven or a slag pocketfor an oven, e. g. a slag pocket of an open hearth.

It has been proposed to break the slag in a slag pocket of an openhearth furnace in the following manner. In the pocket brick supportingwalls are built, upon which refractory tiles are arranged in acontinuous row having a hole through them. Between such supporting wallsrows of tiles can be arranged on the bottom of the pocket. The holes inthe tiles constitute a continuous channel in which, for breaking theslag, explosives can be inserted and exploded. The brick walls forsupporting the tiles have to be rebuilt after explosion, the tubes andthe walls are expensive and take up a considerable part of the efficientspace in the pocket. The slag will tend to arch between the walls sothat the useful space is further reduced.

The insertion of the explosive is quite dangerous because the explosivetends to self-detonation, therefore there should be a delay until theslag body has cooled sufliciently.

-It is an object of the present invention to prevent loss of time andexpense in breaking such deposits.

'It is a further important object of this invention to prevent the oven,furnace or the like to be taken out of operation for too long a time,which has an important effect upon production capacity.

It is a further object of this invention to remove the deposits in asafe way.

The invention is mainly distinguished from the known method of slagremoval in that one or more simple unitary tubes are inserted before orduring operation of the furnace or the like, such tubes being cooled bythe passage of a cooling fluid such as water therethrough duringoperation and said tubes being exploded immediately after stopping thecooling at the end of the operation of the furnace or the like. I

In the drawings a preferred embodiment of a slag pocket for applicationof the method of the invention has been shown and said embodiment willnow be described below.

Fig. 1 is a diagrammatic cross-section of a slag pocket of an openhearth furnace for applying the present invention.

Fig. 2 is a front view of said slag pocket.

Fig. 3 is a cross-section of one of the tubes with connections for thecooling fiuid according to 'this'invention as applicable to slag pocketsaccording to Figs. 1 and 2.

The open hearth furnace is not shown in the drawings. It is positionedabove the part of the plant shown in Figs. 1 and 2. in well known mannerthis furnace has a hearth containing a bath of metal to be refined. Ateach end of said hearth there are two vertical ducts: (1) Each leadingto a slag pocket 2 of which one only is shown. (2) The gases flowingdownwards from the duct 1 to the slag pocket 2 thereafter pass through apassage 3 to the regenerators of well known structure which are notshown in the drawings. Said hot gases heat up the filling of theregenerators and after some time the flow of gases is reversed, air andfuel gas flowing in parallel through separate hot regenerators andthrough passage 3 upwards through duct 1 of each regenerator towards thehearth. Usually there are four regenerators and also four ducts 1 andfour slag pockets 2. Two of said parts are arranged to one side of thefurnace below the hearth and the other two at the other end of thefurnace. Gas and air mix in the hearth and give combustion, flow overthe molten metal in the bath of the hearth and descend at theoppositeside 'of the hearth through both ducts 1 at that side to thecorresponding slag pockets 2 and regenerators to heat up saidregenerators.

The slag particles entrained by the gases form deposits in the slagpocket as shown in Fig. 1, and with a dotted line in Fig. 2. The line inthe drawing gives about the highest level to which the deposits areallowed to collect. Thereafter these deposits should be removed. Theyconstitute a very hard and solid hot mass. The shape of said line maydiffer considerably even in the same plant, between different operationperiods.

According to the invention unitary tubes 4 are inserted in the slagpockets to break up the deposits. Said tubes are preferably simple metaltubes. They are inserted before the deposits begin to form or beforethey are formed sufficiently to cover the points where one wishes toinsert the tubes. I

The tubes 4 may be introduced by sliding them through suitable openingsin the front wall 5 of the slag pocket. Said wall consists of bricks andit is possible to provide scalable holes in several bricks for allowingthe tubes 4 to be inserted, or it is possible to remove the bricksduring operation of the furnace so that a hole is formed through whichthe tube may be inserted, the hole around the tube beingsealedthereafter by some suitable material. At the beginning of the operationof the furnace the lower tubes 4 are inserted. Fig, 2 shows three ofsuch lower tubes. Thereafter, as the deposits collect further, which iscontrolled by looking through one or more inspection openings in theslag pocket wall, and as the deposits have reached a certain level atube 4 is inserted right above the momentary surface of the deposits.When the deposits have filled the slag pocket fully so that breaking andremoving of the deposits becomes necessary there are for instance sixtubes 4 in the pocket at different levels as shown in Fig. 2 in placesdependent on the shape of the slag surface.

It is possible to support the tubes 4 at the back end of the pocket uponsupports 6 made in the pocket for the purpose, e. g. by a stepped shapeof the back wall thereof, but it is also possible to support the tubesat the front end in front of and in the wall 5 only. It is also possibleto have at least the higher tubes 4 rest immediately upon the depositsalready formed when inserting the tubes.

' If the surface of the deposits has a shape different from the shape ofthe drawings the tubes4 could be introduced tube 4 has a flange 1%connected by bolts 11 to a cover open hearth furnaces.

The tubes 4 are inserted as a whole in the condition shown in Fig. 3,with the inner pipe 13 arranged therein. Through hose 15 water is fed topipe 13, said water flowing to the open end 19 of said pipe and backthrough the space between pipes 4 and 13 to the outlet 8. Fig. 2 showsthat the hoses 9 and 15 are connected to horizontal ducts 20 and 21respectively leading along the upper part of the outside ofthe slagpocket, the duct 21 feeding cooling water to the hoses 15 and the duct20 discharging said cooling water again. Evidently if there is ashortage of water it ispossible to have the water move in a closedcircuit with a cooling heat exchanger or cooling tower in the circuit. 7

The flow of the cooling fluid needs only be so that the pipes 4 areprevented from burning and of course it is in general preferable toprevent boiling of the water.

If the slag has to be broken the pipes 4 are drained through the drains16 by opening cock 17 and the hoses 9 and 15 are loosened. Thereafterthe bolts 11 are loosened and the flange 12 with the inner pipe 13 isremoved from the pipe 4. Explosive charges are now inserted, forinstance, in the form of a pipe filled with explosive and closed at bothends with only leads through one end for detonation. Such a pipe couldslide into any pipe 4 immediately after termination of the cooling sothat no danger of self-detonation exists, because the explosive chargescannot become too hot before being exploded intentionally.

After explosion which may take place while the slag body is still toohot to allow personnel to work therein, the loosened slag has to beremoved. This is accomplished by dismantling the front wall so that goodaccess to the space is obtained. No waiting for further cooling of theslag is necessary and it is possible to begin the removing of the slagimmediately after the explosion and the dismantling of the front wallFor removing the loosened slag itself the personnel does not need towork in the space during a too long time, and moreover the space coolsrapidly after dismantling the front wall 5. The exploding of the tubeswill preferably not take place all at the same moment, but the highertubes will preferably be exploded first, either one by one or in While Ihave illustrated and described hereinbefore' one specific embodiment ofmy invention, it will be clear that thisis only by way of illustration.Various changes and modifications may be made therein, and thisinvention is in its application not restricted to slag pockets of Suchchanges and modifications do, however, always fall within the scope ofthe appendant claims.

What I claim is:

l. A method of breaking formations of solid deposits formed in a hotspace such as an oven or a slagpocket for an oven, comprisingintroducing a tube into said space during the formation of the depositsin said space in the region of said space Where such deposits are formedin operation, leading a cooling fluid through said tube during theformation of deposits in said space to preserve said tube, inserting anexplosive into said tube after the forming of the deposits anddetonating said explosive in the furnace to break the tube and thedeposits surround ing it. e

2. A method of breaking formations of solid deposits formed in a hotspace such ,as an ovenor a slag pocket for an oven, comprisingintroducing a metal tube into said space during the formation of thedeposits in said space in the region of said space where such depositsare formed in operation, leading a cooling fluid through said tubeduring the formation of deposits in said space to preserve said tube,inserting explosive into said tube after the forming of the deposits anddetonating said explosive to break the tube and the deposits surroundingit.

3. A method of breaking formations of solid deposits formed in a hotspace, such as an oven or a slag pocket for an oven, comprisingintroducing a plurality of tubes into such a space, a part thereof beingintroduced at the beginning of the operation of the said space close tothe bottom thereof and other tubes being introduced during operationafter partial formation of the deposits at positions immediately abovethe temporary upper surface of the deposits, leading a cooling fluidthrough said tubes to preserve the same, inserting explosive into saidtubes after the complete forming of the deposits and detonating saidexplosive to break the tubes and the deposits surrounding it.

4. A method of'breaking formations of solid deposits formed in a hotspace, such as an oven or a slag pocket of an open hearth-furnace,comprising introducing a first tube and a second tube of smallerdiameter within said first tube into said space before the formation andcompletion of formation of the deposits in said space in the region ofsaid space 'where such deposits are formed in operation, leading acooling fluid through one of said concentric tubes and back through theother in operation of said space to preserve said tubes, the outer tubebeing closed at one end, inserting explosive into said first tube afterthe forming of the deposits and detonating said explosive to break thetube and the deposits surrounding it.

5. A method of breaking formations of solid deposits formed in a hotspace, such as an oven or a slag pocket for an oven, comprisingintroducing a first tube into said space in the region of said spacewhere. deposits are formed during operation, leading a cooling fluidthrough said tube in operation'of said space to preserve said tube,inserting a tube with an explosive slidingly into said first tube afterthe forming of the deposits,- sealing said explosive containing tube atboth ends, and detonating said explosive to break the tube and thedeposits surrounding it.

6. A slag pocket device for a furnace or a similar hot space, in whichduring operation solid deposits are formed which have to be re rnoved atintervals, said pocket comprising a wall, a number of selectivelyoperable and sealable passages in said wall, unitary tubes insertablethrough said passages, by sliding into said pocket, means for feedingacooling fluid tosaid tubes and means for inserting an explosive intosaid tubes and for detonating said expl si r 7. A device as claimed inclaim 6 comprising a plurality of unitary tubes adapted to he slid intosaid slag pocket in which solid deposits are formed in operation, saiddevice further comprising means to feed a cooling fluid to each of saidtubesand means to explode each of said tubes.

References Cited in the file of this patent UNITED STATES PATENTS2,151,264 Cavanaugh Mar. 21, 1939 2,299,892 Gerwig Oct. 27, 19422,664,284 'Fausnaught Dec. 29, 1953

